public Flags() 
{
        user_flags = new Hashtable();
}

Construct a Flags instance with no flags set.

 public Flags(Flags.Flag flag) 
{
        system_flags = flag.mask;
        user_flags = new Hashtable();
}

Construct a Flags instance with a supplied system flag set.

Parameters:

flag - the system flag to set

 public Flags(Flags flags) 
{
        system_flags = flags.system_flags;
        user_flags = new Hashtable(flags.user_flags);
}

Construct a Flags instance with a same flags set.

Parameters:

flags - the instance to copy

 public Flags(String name) 
{
        user_flags = new Hashtable();
        user_flags.put(name.toLowerCase(), name);
}

Construct a Flags instance with the supplied user flags set. Question: should this automatically set the USER system flag?

Parameters:

name - the user flag to set

 public  void add(Flags.Flag flag) 
{
        system_flags |= flag.mask;
}

Set a system flag.

 public  void add(Flags flags) 
{
        system_flags |= flags.system_flags;
        user_flags.putAll(flags.user_flags);
}

Set all system and user flags from the supplied Flags. Question: do we need to check compatibility of USER flags?

 public  void add(String name) 
{
        user_flags.put(name.toLowerCase(), name);
}

Set a user flag. Question: should this fail if the USER system flag is not set?

 public Object clone() 
{
        return new Flags(this);
}

Return a copy of this instance.

 public boolean contains(Flags.Flag flag) 
{
        return (system_flags & flag.mask) != 0;
}

See if the supplied system flags are set

 public boolean contains(Flags flags) 
{
        return ((system_flags & flags.system_flags) == flags.system_flags)
                && user_flags.keySet().containsAll(flags.user_flags.keySet());
}

See if all of the supplied Flags are set

 public boolean contains(String name) 
{
        return user_flags.containsKey(name.toLowerCase());
}

See if the supplied user flag is set

 public boolean equals(Object other) 
{
        if (other == this) return true;
        if (other instanceof Flags == false) return false;
        final Flags flags = (Flags) other;
        return system_flags == flags.system_flags && user_flags.keySet().equals(flags.user_flags.keySet());
}

Equality is defined as true if the other object is a instanceof Flags with the same system and user flags set (using a case-insensitive name comparison for user flags).

 public Flags.Flag[] getSystemFlags() 
{
        // assumption: it is quicker to calculate the size than it is to reallocate the array
        int size = 0;
        if ((system_flags & Flag.ANSWERED.mask) != 0) size += 1;
        if ((system_flags & Flag.DELETED.mask) != 0) size += 1;
        if ((system_flags & Flag.DRAFT.mask) != 0) size += 1;
        if ((system_flags & Flag.FLAGGED.mask) != 0) size += 1;
        if ((system_flags & Flag.RECENT.mask) != 0) size += 1;
        if ((system_flags & Flag.SEEN.mask) != 0) size += 1;
        if ((system_flags & Flag.USER.mask) != 0) size += 1;
        Flag[] result = new Flag[size];
        if ((system_flags & Flag.USER.mask) != 0) result[--size] = Flag.USER;
        if ((system_flags & Flag.SEEN.mask) != 0) result[--size] = Flag.SEEN;
        if ((system_flags & Flag.RECENT.mask) != 0) result[--size] = Flag.RECENT;
        if ((system_flags & Flag.FLAGGED.mask) != 0) result[--size] = Flag.FLAGGED;
        if ((system_flags & Flag.DRAFT.mask) != 0) result[--size] = Flag.DRAFT;
        if ((system_flags & Flag.DELETED.mask) != 0) result[--size] = Flag.DELETED;
        if ((system_flags & Flag.ANSWERED.mask) != 0) result[--size] = Flag.ANSWERED;
        return result;
}

Return a list of Flags containing the system flags that have been set

 public String[] getUserFlags() 
{
        return (String[]) user_flags.values().toArray(new String[user_flags.values().size()]);
}

Return a list of user flags that have been set

 public int hashCode() 
{
        return system_flags ^ user_flags.keySet().hashCode();
}

Calculate a hashCode for this instance

 public  void remove(Flags.Flag flag) 
{
        system_flags &= ~flag.mask;
}

Unset the supplied system flag. Question: what happens if we unset the USER flags and user flags are set?

 public  void remove(Flags flags) 
{
        system_flags &= ~flags.system_flags;
        user_flags.keySet().removeAll(flags.user_flags.keySet());
}

Unset all flags from the supplied instance.

 public  void remove(String name) 
{
        user_flags.remove(name.toLowerCase());
}

Unset the supplied user flag.